Troubleshooting bad roll-in issue unfolded #sapadmin

Introduction

Some weeks ago I received a mail requesting some information on how to go about troubleshooting. In general what I would advice is that you pick up as much issues as possible and of course solve them or try hard to solve them and learn troubleshooting that way as “Do” is one of the most effective ways.

When you have to troubleshoot, knowledge on the topic can of course help you to a significant extent but there are also times you get an issue on your plate in an area you have less experience on. In that case it’s up to you to find the right information online or offline and assess the situation accordingly.

I thought it might be a good idea to blog about such a troubleshooting situation to give some sight on how you can go to work. I already have blogged on several troubleshooting situations in the past so you are also welcome to check out my blog list (you can reach it by clicking on my name on top of this blog).

The issue

In this blog I take a look at how to troubleshoot an error that was reported by the end-users on a SAP system. End-users where receiving SAP Gui errors stating roll-in failed and as an effect their session got terminated.

The end users gets a pop-up from SAP GUI stating Roll-in failed and his/her session is being terminated as an effect.

As always there can be multiple reasons this kind of error is being triggered. When you see the error the most logical answer would be a lack of Roll memory. There are multiple spots where roll memory comes into play.

When you troubleshoot and an issue can have multiple causes it comes down to eliminating the possible causes which are not the root cause.

Picture 1.1

To verify the used Roll memory go to transaction ST02 and double click on Roll area underneath the header SAP Memory.

Picture 1.2

From left to right, Roll Size Used Kb, Maximum Roll Size Used in Kb, Roll Area Size available in Shared Memory and Roll Area Size available on Disk.

How are the values of RSizeInSHM and RollOnDisk calculated?

rdisp/ROLL_SHM defines the roll area size that resides in the shared memory

rdisp/ROLL_MAXFS defines the maximum roll area size of the sum of the shared memory roll area and file roll area

This means the following:

Roll size on disk = rdisp/ROLL_MAXFS – rdisp/ROLL_SHM

The parameter values for rdisp/ROLL_MAXFS and rdisp/ROLL_SHM do not match the values in transaction ST02 because the values in the SAP profiles equals the value in 8KB blocks. This means you have to multiple the value of the parameters (rdisp/ROLL_MAXFS, rdisp/ROLL_SHM) with 8 to be able to know how many KB the Roll area is.

If you look here, the maximum used Roll Size is 466.040 Kb which is less than 393.216 Kb + 393.216 Kb thus the limit is not reached. This means the root cause cannot be solved by any of those parameter settings.

Sources where you can find information on Roll memory:

1627534 – How are the SAP Roll area and Page area set in the SAP system?

SAPPress SAP Performance optimization guide

The question then becomes what could be the root cause then? If it isn’t caused by the roll memory defined by the above parameter settings where can the issue come from then?

My first guess was a problem in the SAP Kernel. Why? There isn’t a lack of memory so for what good reason would a roll-in fail? It could fail because the data rolled in is no good.

How can you check the fixes that have been made to the SAP Kernel compared to the version you are currently on? You can check the SAP Notes which are bound to Kernel versions through SAP Service Marketplace https://service.sap.com/swdc

Picture 1.3

Navigate to the latest available kernel for your SAP system and click on the Info link to the right of the Kernel version. The clue is of course to look into the SAP notes which belong to higher level kernels than the kernel level your SAP system is on.

Picture 1.4

You will get a pop-up with all the notes that apply to the Kernel versions up to the Kernel version you requested info on in SAP Service Marketplace. Start from the actual kernel version of your SAP system and scroll down and check which SAP notes are related.

This note offers the solution to the problem that was detected. By setting the parameter as described in the SAP note (workaround) or by updating the SAP Kernel the issue is resolved.

Conclusion

There are many ways to do troubleshooting as a #sapadmin. An alternative to searching SAP notes on SAP Service Marketplace is checking the SAP Notes info that are related to a certain component. In this example I show the kernel related notes info but this info link is also available for other components.

If you have pinpointed the root cause in a certain component checking the component info link and all the notes related to the component version(s) is definitely an interesting source of information.

Troubleshooting is a form of art. The key is always to find the right information.